Arquitetura de Computadores Princípios de Projeto de Computadores

Benchmark Games
•An embarrassed Intel Corp. acknowledged Friday that a bug in a software
program known as a compiler had led the company to overstate the speed
of its microprocessor chips on an industry benchmark by 10 percent.
However, industry analysts said the coding error…was a sad commentary
on a common industry practice of “cheating” on standardized performance
tests…The error was pointed out to Intel two days ago by a competitor,
Motorola …came in a test known as SPECint92…Intel acknowledged that it
had “optimized” its compiler to improve its test scores. The company had
also said that it did not like the practice but felt to compelled to make the
optimizations because its competitors were doing the same thing…At the
heart of Intel’s problem is the practice of “tuning” compiler programs to
recognize certain computing problems in the test and then substituting
special handwritten pieces of code…
Saturday, January 6, 1996 New York Times
SPEC ‘89
• Compiler “enhancements” and performance
800
700
600
SPEC performance ratio
500
400
300
200
100
0
gcc
espresso
spice
doduc
nasa7
li
eqntott
matrix300
fpppp
tomcatv
Benchmark
Compiler
Enhanced compiler
10